Test method and program product used therefor

ABSTRACT

The testing method of the present invention for testing a plurality of devices under test connected to a test module includes (a) determining combinations of devices under test that can theoretically be measured simultaneously from among the combinations of the plurality of devices under test based on at least the connection relationship between the test module and the plurality of devices under test. The resting method further includes (b) testing the plurality of devices under test by sequentially selecting the combinations of devices under test to be actually measured simultaneously from the combinations determined in (a).

BACKGROUND

1. Technical Field

The present invention relates to a testing method for an electronicdevice, such as a semiconductor device, and a program product usedtherein, and particularly, to a method for testing a plurality ofdevices under test connected to a test module.

2. Related Art

As a conventional testing method, a method for simultaneously measuringa plurality of devices under test by connecting only one device undertest to one segment of a test module is known. In this case, since it ispossible to simultaneously control a plurality of segments, a pluralityof devices under test can be tested simultaneously via a singlemeasurement. However, only one device under test can be allocated to onesegment in this connection relationship, and the number of devices undertest capable of being tested per one-time connection is limited.

Conversely, when a user connects two or more devices under test to onesegment of a test module to make effective use of the test module'sexternal terminals, the two or more devices under test connected persegment cannot be measured at the same time as one another, therebyrequiring that a number of measurements be carried out per test. When alarge number of devices under test are connected to the test module inthis case, it is difficult for the user to arbitrarily select thesequence in which the devices under test are to be measured, and it iseven more difficult to select a sequence that has a minimal number ofmeasurements.

SUMMARY

Accordingly, an object of the present invention is to provide a testingmethod and program product capable of solving for the above problems.The object will be attained by combining features disclosed in theindependent claims of the Claims. The dependent claims will recite moreadvantageous concrete examples of the present invention.

According to a first aspect of the present invention for achieving theabove object, there is provided a testing method for testing a pluralityof devices under test connected to a test module, comprising (a)determining combinations of devices under test that can theoretically bemeasured simultaneously from among the combinations of the plurality ofdevices under test, based on at least the connection relationshipbetween the test module and the plurality of devices under test, and (b)testing the plurality of devices under test by sequentially selectingthe combinations of devices under test to be actually measuredsimultaneously from the combinations determined in (a).

In the testing method, carrying out (a) and (b) makes it possible totest using the number of measurements that is less than the number ofthe plurality of devices under test connected to the test module.

In the testing method, the test module has a plurality of segments, andin (a), the combinations of devices under test that are unable to bemeasured simultaneously can be determined for each of the segments fromamong the combinations of the plurality of devices under test, and thecombinations of devices under test that are theoretically able to bemeasured simultaneously can be determined based on these combinations.

In (b) of the testing method, the combinations of devices under test tobe actually measured simultaneously can be selected in ascending orderfrom the smallest number of devices under test that are able to bemeasured simultaneously.

In (b) of the testing method, the combinations of devices under test tobe actually measured simultaneously can be selected in descending orderfrom the largest number of devices under test that are able to bemeasured simultaneously.

In (b) of the testing method, the combinations of devices under test tobe actually measured simultaneously can be selected in the order ofnumbers pre-allocated to the devices under test.

According to a second aspect of the present invention, there is provideda program product that is used for testing a plurality of devices undertest connected to a test module, this program product causing a computerto execute a process that comprises (a) generating combination data fordevices under test that can theoretically be measured simultaneouslyfrom among the combinations of the plurality of devices under test,based on at least the connection relationship between the test moduleand the plurality of devices under test, and (b) testing the pluralityof devices under test by sequentially selecting the combinations ofdevices under test to be actually measured simultaneously from thecombination data generated in (a).

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram for illustrating a testing method according to anembodiment of the present invention.

FIG. 2 is a diagram for illustrating a program product according to anembodiment of the present invention.

FIG. 3 is a diagram showing an example of a connection relationshipbetween a test module and devices under test according to an embodimentof the present invention.

FIG. 4 is a diagram showing the combinations of devices under test thatare unable to be measured simultaneously in each segment in theconstitution shown in FIG. 3.

FIG. 5 is a diagram showing combinations of devices under test that cantheoretically be measured simultaneously in the constitution shown inFIG. 3.

FIG. 6 is a flowchart of the testing method according to an embodimentof the present invention.

DESCRIPTION OF EXEMPLARY EMBODIMENTS

The present invention will be explained below using the embodiments ofthe invention while referring to the drawings, but the followingembodiments do not limit the claimed invention, and not all of thecombinations of features explained in the embodiments are required asthe solution of the invention.

FIG. 1 is a diagram for illustrating a testing method related to a firstembodiment of the present invention. In this embodiment, a plurality ofdevices under test (DUT) 20 are tested using the testing apparatus 10shown in FIG. 1. Specifically, the testing apparatus 10 generates aprescribed test signal, supplies the test signal to a DUT 20, anddetermines if the DUT 20 is “Pass” or “Fail” based on whether or not aresult signal, which outputs the result of the DUT 20 operation on thebasis of the test signal, coincides with an expected value. The testingapparatus 10 related to the embodiment is realized in accordance with anopen architecture, and an open architecture-based module can be used asthe test module 150 that supplies the test signal to the DUT 20.

As shown in FIG. 1, the testing apparatus 10 comprises a system controldevice 100, DUT selection control device 110, communication network 120,site control device 130, connection configuration device 140, testmodule 150 and load board 160. A user can arbitrarily combine the sitecontrol device 130 and the test module 150 in accordance with the numberof DUT 20 external terminals, the DUT 20 configuration, such as thenumber of functional blocks, and the nature of the test, and make use ofthis combination via the system control device 100.

The system control device 100 stores a test control program, testingprogram, and test data, which the testing apparatus 10 uses to test theDUT 20. The system control device 100, for example, can be connected toa plurality of site control devices 130 via the communication network120, the plurality of site control devices 130, for example, can beconnected to a plurality of test modules 150 via the connectionconfiguration device 140, and the plurality of test modules 150, forexample, can be connected to a plurality of DUT 20 via the load board160. Thus, providing a connection configuration device 140 and a loadboard 160 makes it possible to freely configure and change theinterconnection relationships of the site control device 130, testmodule 150 and DUT 20.

FIG. 2 is a diagram showing details of a DUT selection control device110 shown in FIG. 1. The DUT selection control device 110 is a programproduct in which a prescribed program for carrying out the testingmethod is pre-installed. The DUT selection control device 110 comprisesas a primary constitution a control unit 112 for controlling theprocessing for testing, and a storage unit 113 for storing the dataneeded for testing. By executing either a prescribed program that isstored in an external storage device or the like, or a prescribedprogram that is capable of being downloaded via a communication network,the DUT selection control device 110 can also cause a testing method,which will be described in detail below, to be executed in the testingapparatus 10. Also, the DUT selection control device 110 can be disposedindependently of the system control device 100 as shown in FIG. 1, orcan be incorporated as a part of either the system control device 100 orthe site control device 130.

The control unit 112 of the DUT selection control device 110 shown inFIG. 2 comprises as a primary constitution a DUT combination datageneration part 114 and a DUT combination selection part 118. The DUTselection control device 110 (for example, the control unit 112) canadditionally have a DUT combination data display part 116. Therespective functional blocks are connected to a storage unit 113, andconsequently, the information, which is processed by the above-mentionedrespective functional blocks, and which is needed in the testing method,can be either written to the storage unit 113 or read out from thestorage unit 113. An explanation of the respective functional blocks canbe obtained by referring to the explanation of the testing methodprovided below.

In the testing method related to this embodiment, a user tests aplurality of DUTs that have been connected to the test module 150 in aprescribed connection relationship. In this case, testing can be carriedout using a number of measurements that is less than the number of theplurality of DUTs connected to the test module 150. That is, when n (nbeing an integer of 2 or greater) DUTs are connected to the test module150, all of the DUTs can be tested using at the most (n−1) measurementsby simultaneously measuring at least two DUTs in a single measurement.The testing method related to this embodiment will be explained indetail by referring to FIGS. 3 through 5. However, the testing methodrelated to this embodiment is not limited to the examples of theconstitution of FIGS. 3 through 5.

FIG. 3 is a diagram showing an example of a connection relationshipbetween the test module and the devices under test related to thisembodiment. In the example shown in FIG. 3, modules (for example,digital modules) 150 a through 150 d, which are an example of a testmodule 150, and a plurality of DUTs 20 a through 20 f are connected toone another. The modules 150 a through 150 d each have at least onesegment, which is the smallest operating unit, and there is a patterngenerator PG and formatter FMT for each segment. The respective modules150 a through 150 d also each have a plurality of external terminals152, and the DUTs 20 a through 20 f are connected to the test module 150by these external terminals 152 being connected to the externalterminals 22 of the DUTs.

Modules 150 a through 150 c are the same (Type A), and can be controlledusing the same control method. For example, modules 150 a through 150 ccan each be controlled using the same type of synchronized signal. Bycontrast, module 150 d is a different type than modules 150 a through150 c (Type B), and can be controlled using a method (for example, adifferent type of synchronization signal) that differs from that ofmodules 150 a through 150 c. The constitutional difference is thatmodules 150 a through 150 c each have two segments 150 a-1 through 150c-2, and, by contrast, module 150 d has one segment 150 d-1.

In the example shown in FIG. 3, the respective segments 150 a-1 through150 d-1 each have three external terminals 152, and only one DUTexternal terminal 22 can be connected to one of the external terminals152. Furthermore, the module-DUT connection relationship is not limitedto a configuration in which only one DUT external terminal is able toconnect to one module external terminal, and a plurality of externalterminals of either the same or different DUTs can connect to one moduleexternal terminal, or a plurality of external terminals of either thesame or different modules can connect to one DUT external terminal.

Furthermore, the constitution of the module, number of modules, numberof module external terminals, number and constitution of modulesegments, number of DUT external terminals, control method required fora DUT external terminal, and module-DUT connection relationship are notlimited to the constitution example of FIG. 3, and can be either set orchanged at one's discretion within the scope of common general technicalknowledge.

The connection relationship between the modules 150 a through 150 d andthe DUTs 20 a through 20 f shown in FIG. 3 will be described in detailbelow. That is, in module 150 a, the first through the third externalterminals of segment 150 a-1 (The first, second and third externalterminals in order from the top of FIG. 3. Hereinafter, the same willapply to the other segments or DUTs as well.) are respectively connectedto the first and second external terminals of DUT 20 a and the firstexternal terminal of DUT 20 b, and the first through the third externalterminals of segment 150 a-2 are connected to the second and thirdexternal terminals of DUT 20 b, and the first external terminal of DUT20 d. In module 150 b, the first and second external terminals ofsegment 150 b-1 are respectively connected to the third externalterminal of DUT 20 a and the first external terminal of DUT 20 f, thethird external terminal of segment 150 b-1 is not connected to any DUT,and the first through the third external terminals of segment 150 b-2are respectively connected to the first and second external terminals ofDUT 20 c and the second external terminal of DUT 20 d. In module 150 c,the first through the third external terminals of segment 150 c-1 arerespectively connected to the third external terminal of DUT 20 c andthe first and second external terminals of DUT 20 e, the first andsecond external terminals of segment 150 c-2 are respectively connectedto the third external terminal of DUT 20 d and the second externalterminal of DUT 20 f, and the third external terminal of segment 150 c-2is not connected to any DUT. In module 150 d, the first and secondexternal terminals of segment 150 d-1 are respectively connected to thethird external terminal of DUT 20 e and the third external terminal ofDUT 20 f, and the third external terminal of segment 150 d-1 is notconnected to any DUT.

Connecting two or more DUTs to one segment like this can eliminate idleexternal terminals 152 on the test module 150, and increase the numberof DUTs that can be measured simultaneously.

The testing method related to this embodiment first determines thecombinations of DUTs that can theoretically be measured simultaneouslyfrom among combinations of the plurality of DUTs based on at least theconnection relationship between the test module 150 and the plurality ofDUTs 20 a through 20 f.

FIGS. 4 and 5 here are diagrams illustrating the steps for determiningthe combinations of devices under test that can theoretically bemeasured simultaneously in the constitution shown in FIG. 3. Further,FIG. 6 is a flowchart of the testing method related to this embodiment.

First, as shown in FIG. 4, the combinations of devices under test thatare able to be measured simultaneously by segment are determined basedon at least the connection relationship between the modules 150 athrough 150 d and the DUTs 20 a through 20 f shown in FIG. 3 (Step 101).In FIG. 4, S₀ through S₆ respectively correspond to segments 150 a-1through 150 d-1 of FIG. 3, and DUTs 1 through 6 correspond to DUTs 20 athrough 20 f of FIG. 3. The “1” displayed in FIG. 4 signifies thatsimultaneous measurements are not possible, and the “0” signifies thatsimultaneous measurements are possible. For example, in S₀, whichcorresponds to segment 150 a-1, a “1” is displayed in DUT 1(corresponding to DUT 20 a of FIG. 3) and DUT 2 (corresponding to DUT 20b of FIG. 3), denoting that DUTs 1 and 2 cannot be measuredsimultaneously.

As is clear from the combination data of FIG. 4, combinations that areunable to be measured simultaneously in the connection relationshipbetween the modules and DUTs shown in FIG. 3 are DUTs 1 and 2 in S₀,DUTs 2 and 4 in S₁, DUTs 1 and 6 in S₂, DUTs 3 and 4 in S₃, DUTs 3 and 5in S₄, DUTs 4 and 6 in S₅, and DUTs 5 and 6 in S₆.

Next, the DUT combinations that can theoretically be measuredsimultaneously are determined based on the combination data of FIG. 4 asshown in FIG. 5 (Step 103). In FIG. 5, DUTs 1 through 6 respectivelycorrespond to DUTs 20 a through 20 f of FIG. 3. Also, the “1” displayedinside FIG. 5 signifies that simultaneous measurements are possible, andthe “0” displayed inside FIG. 5 signifies that simultaneous measurementsare not possible. For example, in the DUT 1 row in FIG. 5, “1” isdisplayed in DUTs 1, 3, 4 and 5, denoting that DUTs 3, 4 and 5 are theother DUTs that can theoretically be measured simultaneously with DUT 1.

As is clear from the combination data of FIG. 5, the DUT combinationsthat can theoretically be measured simultaneously in the connectionrelationship between the modules and DUTs shown in FIG. 3 are DUTs 3, 4and 5 for DUT 1, DUTs 3, 5 and 6 for DUT 2, DUTs 1, 2 and 6 for DUT 3,DUTs 1 and 5 for DUT 4, DUTs 1, 2 and 4 for DUT 5, and DUTs 2 and 3 forDUT 6.

The combination data shown in FIGS. 4 and 5 like this, for example, canbe generated by the DUT combination data generation part 114 (See FIG.2). Further, generated combination data can be stored in the storageunit 113, and can also be displayed on a display or the like by the DUTcombination data display part 116 (See FIG. 2) such that the user canrecognize this combination data.

In the above-mentioned embodiment, after generating the combination dataof FIG. 4 (that is, the combination data for DUTs that can be measuredsimultaneously expressed for each segment), the combination data of FIG.5 was generated based on this combination data, but this embodiment isnot limited to this. For example, the DUT combination data generationpart 114 can directly generate the combination data of FIG. 5 based onat least the connection relationships between the modules 150 a through150 d and the DUT 20 a through 20 f shown in FIG. 3, and only thecombination data of FIG. 5 can be displayed by the DUT combination datadisplay part 116. Furthermore, the mode of the combination data displayis not limited to the examples shown in FIGS. 4 and 5.

Next, DUT combinations to be actually measured simultaneously aresequentially selected from the DUT combinations shown in FIG. 5, and aplurality of DUTs is tested (Step 105). That is, after taking intoaccount the propriety of measuring all of the plurality of DUTs, the DUTcombinations that are to actually be measured simultaneously aresequentially selected based on the DUT combinations of FIG. 5, and aplurality of DUTs is tested in accordance with this sequence.

This step can be carried out by the DUT combination selection part 118(See FIG. 2). For example, the DUT combination selection part 118selects the sequence of the DUTs to be measured in accordance with apredetermined rule. As this selection method, for example, there is amethod for carrying out selection in the order of numbers pre-allocatedto the DUTs (hereinafter, referred to also as selection method (A)), amethod for carrying out selection in ascending order from the smallestnumber of DUT that can be measured simultaneously (hereinafter, referredto also as selection method (B)), and a method for carrying outselection in descending order from the largest number of DUTs that canbe measured simultaneously (hereinafter, referred to also as selectionmethod (C)).

The above-mentioned selection methods (A) through (C) are applied to theDUT combinations of FIG. 5 as follows.

When selection method (A) is used, attention focuses on DUT 1 first inaccordance with the sequence of the DUT numbers. As shown in FIG. 5,DUTs 3, 4 and 5 can theoretically be measured simultaneously with DUT 1,and attention focuses on DUT 3 in accordance with the sequence of theDUT numbers. As shown in FIG. 5, since DUTs 4 and 5 are not able to bemeasured simultaneously with DUT 3, it is clear that DUTs 1 and 3 areactually able to be measured simultaneously. Next, attention focuses onDUT 2 in accordance with the sequence of the DUT numbers. As shown inFIG. 5, DUTs 3 and 5 can be measured simultaneously with DUT 2, andsince DUT 3 has already been measured, it is clear that DUTs 2 and 5 areactually able to be measured simultaneously. Next, attention focuses onDUT 4 in accordance with the sequence of the DUT numbers. As shown inFIG. 5, DUTs 1 and 5 can theoretically be measured simultaneously withDUT 4, and since DUTs 1 and 5 have already been measured, it is clearthat only DUT 4 is actually able to be measured simultaneously. Finally,DUT 6, which is the last DUT remaining, is measured.

When selection method (A) is used like this, DUTs 1 and 3 are measuredin the first round of measurements, DUTs 2 and 5 are measured in thesecond round of measurements, DUT 4 is measured in the third round ofmeasurements, and DUT 6 is measured in the fourth round of measurements.That is, when selection method (A) is used in the connectionrelationship between the modules and DUTs shown in FIG. 3, all of theDUT can be tested using a total of four measurements.

Next, when selection method (B) is used, attention focuses on DUT 6,which, as is clear from FIG. 5, has the smallest number of DUT that canbe measured simultaneously. As shown in FIG. 5, DUTs 2 and 3 cantheoretically be measured simultaneously with DUT 6, and since DUTs 2and 3 can also theoretically be measured simultaneously with oneanother, it is clear that DUTs 2, 3 and 6 are actually able to bemeasured simultaneously. Next, since the number of DUTs that are able tobe measured simultaneously is the same for all the remaining DUTs 1, 4and 5, for example, attention focuses on DUT1. As shown in FIG. 5, DUTs4 and 5 can theoretically be measured simultaneously with DUT 1, andsince DUTs 4 and 5 can also theoretically be measured simultaneouslywith one another, it is clear that DUTs 1, 4 and 5 are actually able tobe measured simultaneously.

When selection method (B) is used like this, DUTs 2, 3 and 6 aremeasured in the first round of measurements, and DUTs 1, 4 and 5 aremeasured in the second round of measurements. That is, when selectionmethod (B) is used in the module-DUT connection relationship shown inFIG. 3, all of the DUTs can be tested using two measurements.

Next, when selection method (C) is used, DUTs 1 through 5 have thelargest number of DUTs able to be measured simultaneously as is clearfrom FIG. 5, and, for example, attention focuses on DUT 1. As is shownin FIG. 5, DUTs 4 and 5 can theoretically be measured simultaneouslywith DUT 1, and since DUTs 4 and 5 can also theoretically be measuredsimultaneously with one another, it is clear that DUTs 1, 4 and 5 areactually able to be measured simultaneously. Next, of the remaining DUTs2, 3 and 6, DUTs 2 and 3 have the largest number of DUTs that can bemeasured simultaneously, and, for example, attention focuses on DUT 2.As is shown in FIG. 5, DUTs 3, 5 and 6 can theoretically be measuredsimultaneously with DUT 2, and since DUT 5 has already been measured andDUTs 3 and 6 can be measured simultaneously with one another, it isclear that DUTs 2, 3 and 6 are actually able to be measuredsimultaneously.

When selection method (C) is used like this, DUTs 1, 4 and 5 aremeasured in the first round of measurements, and DUT 2, 3 and 6 aremeasured in the second round of measurements. That is, when selectionmethod (C) is used in the module-DUT connection relationship shown inFIG. 3, all of the DUTs can be tested using two measurements.

As described above, it is clear that selection methods (B) and (C) usetwo times fewer the number of measurements than selection method (A) inthe module-DUT connection relationship shown in FIG. 3. For example, theDUT combination selection part 118 sequentially selects the respectiveDUT combinations to be actually measured simultaneously based on theabove-mentioned selection methods (A) through (C), and the selectionmethod in which there are minimal number of measurements can be selectedfrom these selection methods. Or, the number of measurements when usingselection methods (A) through (C) can be stored in advance in thestorage unit 113 for each multiple module-DUT connection relationship,the selection method that constitutes the least number of measurementscan be predetermined from the data stored in the storage unit 113, andthis selection method can be executed.

According to this embodiment, even when a user arbitrarily connects amodule and a DUT, in particular, even when two or more DUTs areconnected to a single module, a plurality of DUTs can be efficientlytested using the least number of measurements possible. That is, thenumber of DUTs that are able to be tested in a one-time module-DUTconnection can be increased as much as possible, and the testing timeper one-time connection can be shortened.

Further, finding a solution to the DUT measurement sequence such thatthere are theoretically a minimum number of measurements either becomesimpossible or takes a very long time when a large number of DUTs isconnected to the test module, but the testing method related to thisembodiment makes it possible to effectively reduce the number ofmeasurements despite the fact that it is easy and takes relativelylittle time to calculate the DUT measurement sequence (combinations).Accordingly, DUT test preparation time and actual testing time can begreatly reduced.

Furthermore, in the above-mentioned constitution example of FIG. 3, theexample of the test module 150 presented is one in which the module hassegments 150 a-1 through 150 d-1, a plurality of external terminals 152is allocated to each segment, and only one external terminal 22 of a DUTcan be connected to one external terminal 152, but the configuration ofthe test module 150 is not limited to this. For example, the test module150 can also have an external terminal as a segment, which is thesmallest operating unit. In this case, the test module 150 can have aplurality of external terminals (in broad terms, a “segment”), and twoor more external terminals of either the same or different DUTs canshare a single external terminal. That is, this embodiment can beapplied to a “resource sharing” configuration in which a test moduleexternal terminal or the external terminal circuitry mounted on a loadboard is shared by the plurality of external terminals of a DUT.

The working examples and applications explained using theabove-described embodiment of the invention can be utilized by eitherarbitrarily combining or making changes or improvement to same inaccordance with the use, and the present invention is not limited to thedisclosure of the above-described embodiment. It is clear from thedisclosure of the Claims that a configuration that adds either acombination, or change or improvement like this can also be includedwithin the technical scope of the present invention.

1. A testing method for testing a plurality of devices under testconnected to a test module, comprising: (a) determining combinations ofdevices under test that can theoretically be measured simultaneouslyfrom among the combinations of the plurality of devices under test,based on at least the connection relationship between the test moduleand the plurality of devices under test; and (b) testing the pluralityof devices under test by sequentially selecting the combinations ofdevices under test to be actually measured simultaneously from thecombinations determined in (a).
 2. The testing method according to claim1, wherein, by carrying out (a) and (b), testing is performed with thenumber of measurements that is less than the number of the plurality ofdevices under test connected to the test module.
 3. The testing methodaccording to claim 1, wherein the test module has a plurality ofsegments, and in (a), combinations of devices under test that are unableto be measured simultaneously are determined for each of the segmentsfrom among the combinations of the plurality of devices under test, andcombinations of devices under test that can theoretically be measuredsimultaneously are determined based on these combinations.
 4. Thetesting method according to claim 1, wherein the combinations of devicesunder test to be actually measured simultaneously are selected in (b) inthe sequence of numbers pre-allocated to the devices under test.
 5. Thetesting method according to claim 1, wherein the combinations of devicesunder test to be actually measured simultaneously are selected in (b) inascending order from the smallest number of devices under test that canbe measured simultaneously.
 6. The testing method according to claim 1,wherein the combinations of devices under test to be actually measuredsimultaneously are selected in (b) in descending order from the largestnumber of devices under test that can be measured simultaneously.
 7. Aprogram product, which is used for testing a plurality of devices undertest connected to a test module, the program product causing a computerto execute a process comprising: (a) generating combination data fordevices under test that can theoretically be measured simultaneouslyfrom among the combinations of the plurality of devices under test,based on at least the connection relationship between the test moduleand the plurality of devices under test; and (b) testing the pluralityof devices under test by sequentially selecting the combinations ofdevices under test to be actually measured simultaneously from thecombination data generated in (a).